The teats protruding from the udder or bag of a dairy animal such as a cow can be uneven in both elevation and angle. First, it is known that immediately prior to milking when the bag is full, the teats typically protrude with a normal angularity to the surface of the udder or bag. As milking proceeds, this angularity changes--typically angularly downward toward the vertical--as the bag empties of milk.
Furthermore, with individual dairy animals, teat angularity and elevation varies from animal to animal. This variation can depend on the overall size of the animal's bag, the age of the animal, the animals breed and heredity, and countless other factors.
Complicating the uneven and varying angularity of the teats is the need to suspend the weight of the teat cup assembly from the teats of the cow. Where one teat carries more weight of the teat cup assembly than the remain teats, several deleterious effects can follow. Since the teat cup assembly is supported from the individual teats, given a rigid teat cup assembly, the higher teat supports a disproportionate amount of the weight. This can strain or irritate the teat, leading to a loss of production.
Worse, such uneven teat cup distribution can lead to teat cup "squawking." Simply stated, the vacuum apparatus grasping the teat leaks across the flesh of the teat to atmosphere making an audible sound. As this noise is accompanied by teat irritation, the dairy operator must make immediate adjustment.
The problem of adjusting to varying teat angularity and elevation has been addressed in the prior art. See Bertao, U.S. Pat. No. 3,094,099. In this device, the weight of a teat cup assembly is supported by a strap from the cow or by a mechanical arm from the side of the milking stall. Each teat cup assembly is free to move on an independent path up and down relative to the teats and bag of a cow. This device thus requires auxiliary support, independent suspension and manifolding for each teat, and does not make accommodation for varying angularity of the teats, either as a result of the biological variation of the dairy animal or the fullness of the udder.